One major strategy to increase the level of zinc (Zn) and iron (Fe) in cereal crops, is to exploit the natural genetic variation in seed concentration of these micronutrients. Genotypic variation for Zn and Fe concentration in seeds among cultivated wheat cultivars is relatively narrow and limits the options to breed wheat genotypes with high concentration and bioavailability of Zn and Fe in seed. Alternatively, wild wheat might be an important genetic resource for enhancing micronutrient concentrations in seeds of cultivated wheat. Wild wheat is widespread in diverse environments in Turkey and other parts of the Fertile Crescent (e.g. Iran, Iraq, Lebanon, Syria, Israel and Jordan). A large number of accessions of wild wheat and of its wild relatives were collected from the Fertile Crescent and screened for Fe and Zn concentrations, and other mineral nutrients. Among wild wheat, the collections of wild emmer wheat, Triticum turgidum subsp. dicoccoides [Triticum dicoccoides] (825 accessions) showed impressive variation and the highest concentrations of micronutrients, significantly exceeding those of cultivated wheat. The concentrations of Zn and Fe among the dicoccoides accessions varied from 14 to 190 mg/kg dry weight (DW) for Zn and from 15 to 109 mg/kg DW for Fe. Moreover, for total amount of Zn and Fe per seed, dicoccoides accessions contained very high amounts of Zn (up to 7 µg per seed) and Fe (up to 3.7 µg per seed). Such high genotypic variation was no observed for phosphorus, magnesium and sulfur. In the case of modern cultivated wheat, seed concentrations of Zn and Fe were lower and less variable compared to wild wheat accessions. There was a highly significant positive correlation between seed concentrations of Fe and Zn. Screening different series of dicoccoides substitution lines revealed that the chromosome 6A, 6B, and 5B of dicoccoides resulted in greater increase in Zn and Fe concentration compared to their recipient parent and to other chromosome substitution lines.
Cakmak, I.; Torun, A.; Millet, E.; Feldman, M.; Fahima, T.; Korol, A.; Nevo, E.; Braun, H.J.; Özkan, H. Triticum dicoccoides: An important genetic resource for increasing zinc and iron concentration in modern cultivated wheat. Soil Science and Plant Nutrition (2004) 50 (7) 1047-1054. [DOI: 10.1080/00380768.2004.10408573]